[Delphinus]

Dez, if I could just jump in here for a second ... as far as I'm concerned, you may as well be getting yourself the holy grail of mogul socket halides. Unless heat or electricity costs are really running against you, my suggestion to you is run them for at least 10 hours. Give your tank an hour on each side for dusk and dawn if you want, and there's your 12 hours. Done deal. Or run them the full 12 hours. Your corals will LOVE you for it.

Seriously. You'll be amazed the results you get (unless you start overheating your tank, but, it sounds like you're well on your way to keeping that under control too).

I'm never going back to a 6 hour halide photoperiod (I ran mine that way for the first year I had halides). When I discovered an issue with my wiring with my fluorescents (the insulation had corroded off), I simply discontinued the fluorescents altogether and switched the halides to a full 12 hours. I originally fully intended to replace the wiring and go back to the way things were, except, that, things were so much happier under the halides for 12 hours that I simply kept things that way. As you know, my 50g and my 20g don't even have fluorescents, I just use the halides. I can only imagine how awesome things would be if I could afford the bluewave ballasts and the 400W radiums. That will be an upgrade for next year maybe, once I've gotten a fair shaked out of my iwasaki's.

Just my $0.02 ....